1. Field of the Invention
The present invention relates to a headlamp, and more specifically to a peephole provided to read an aiming device, which is called VHAD (Vehicle Headlamp Aiming Device), of a headlamp in which an aiming device is built-in so as to effect external aiming without using an aiming device.
2. Description of the Prior Art
A conventional peephole 90 of this kind is shown in FIGS. 3 and 4. A housing 80 is formed with an opening portion 91 having a circular shape, for example, provided with an externally projecting frame portion 91a and is further provided with bosses 92 at suitable places, for example, at three places. A window glass 93 formed, for example, of transparent resin, is threadedly mounted on the opening portion 91 making use of the bosses 92. In order to secure an airtightness between the opening portion 91 and the window glass 93, a gasket groove 93a is provided at a position in the peripheral edge on the housing 80 side of the window glass 93, and a seal gasket 94 formed from a soft member, for example, such as a rubber member, is fitted therein. The seal gasket 94 is compressed by the frame portion 91a and the window glass 93 through screws 95 to provide an airtight construction.
However, in the aforementioned conventional peephole 90, when it is mounted, it requires an extremely troublesome work, for example, threaded mounting by use of three screws 95.
Further, when the built-in aiming device does not display a predetermined value during the shipment inspection of headlamps, it is necessary to remove the window glass 93 of the peephole 90 to readjust the aiming device. In this case, in the peephole 90 constructed as described above, it takes much time to mount and remove it, giving rise to a problem in that a working efficiency in the production line of headlamps is impaired.